92 Cincinnati Society of Natural History. 
by a ring-like wall composed of a dark, and. concentrically laminated 
sclerenchyma. Their walls are sometimes in contact at limited points, 
but usually they are separated from each other by one or two rows of 
angular, and very thin-walled interstitial tubes. The presence of a 
few very small spiniform tubuli constitutes an inconspicuous feature 
of these sections. 
Vertical sections (Pl. I, fig. 50) show that the tubes immediately 
after their development, proceed upward for a short distance in an 
oblique direction, forming an angle of about 45° with the epithecal 
membrane. Soon after their walls become thickened, and their 
direction is altered so that they proceed at a right angle to the upper 
surface. The larger tubes in their lower part are crossed by straight 
diaphragms, one tube-diameter or less distant from each other. 
Further up they are remote and placed on a level in nearly all the tubes: 
The interstitial tubes are developed very near the epitheca, and are 
provided with numerous straight diaphragms. 
At this time the species above described is the only one certainly 
known to belong to the genus Calloporella. There are, however, cer- 
tain Upper Silurian species, which further investigations will probably 
prove to be congeneric. The transverse section of C. harris, reminds 
one considerably of Fistulipora, but I know of no species of that genus 
in which the walls of the proper zooecia are so thick. The surface 
characters of the zoarium, such as the cell-apertures and walls, are 
however clearly such as characterize the Monticuliporide, and not the 
Fistuliporide, the cell orifices in the latter being always surrounded 
by a more or less developed rim or lip. The affinities indicated by the 
surface characters are fully substantiated by vertical sections, which 
show that the interstitial spaces are crossed by straight and complete 
diaphragms, instead of being occupied by a vesicular structure, such 
as is characteristic of all the Pistuliporide. 
The Cincinnati group furnishes several species having a similar 
habit of growth, but they are all limited to the lower half of the group, 
while C. harrisi is found only in the upper part. In its internal struc- 
ture it differs widely from them all. 
Formation and locality: Cincinnati group. Rather common in the 
upper part of the group at Oxford, Blanchester, Westborough, and 
other localities in southwestern Ohio. 
[TO BE CONTINUED. | 
go fd 
